Firearm firing mechanism with disconnector



A. J. LlZZA 2,992,597

FIREARM FIRING MECHANISM WITH DISCONNECTOR 3 Sheets-Sheet 1 July 18, 1961 Filed Dec. 3, 1959 IE ig -E INVENTOR.

71 M s a-dQ/ Z- July 18, 1961 A. J. LIZZA 2,992,597

' FIREARM FIRING MECHANISM WITH DISCONNECTOR Filed Dec. 3, 1959 3 Sheets-Sheet 2 INVENTOR. Alb E r1 J Liz 2.11

2 scy BY July 18, 1961 A. J. LIZZA FIREARM FIRING MECHANISM WITH DISCONNECTOR Filed Dec. 3. 1959 INVENTOR.

A lEe-nl J .Li z 2.1:.

3 Sheets-Sheet 3 4 WWW-4%? 2,992,597 FIREARM FIRING MECHANISM WITH DISCONNECTOR Albert J. Lizza, Willimansett, Mass, assignor to the United States of America as represented by the Secretary of the Army Filed Dec. 3, 1959, Ser. No. 857,233 Claims. (Cl. 89-145) (Granted under Title '35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention relates to the firearms in which the operating mechanism is actuated by discharge forces and more particularly to those firearms wherein the scar and trigger are automatically disconnected during each firing cycle to effect semiautomatic operation.

It is an object of this invention to provide for such firearms a trigger mechanism in which the cooperating parts are rotatingly disposed to provide direct in-line connection between an actuating cable and the sear actuator and add little to the outside contours of the firearm.

It is another object of this invention to provide such firing mechanism with a rotatable sear which has a camming engagement with the firing pin so arranged that the sear returns to full engagement with the firing pin if it should be disengaged partially therefrom.

It is a further object of this invention to provide a semiautomatic firing mechanism which assures full return of the bolt assembly to locked battery position before the sear can be actuated for release of the firing pin.

It is still another object of this invention to provide a semiautomatic firing mechanism which is positive in operation, rugged in construction and easy to manufacture.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

FIG. 1 is a reduced side view of a firearm with the firing device of this invention mounted thereon;

FIG. 2 is a partially cross-sectioned side view of the firearm shown ready to be fired;

FIG. 3 is an enlarged partially cross-sectioned side view similar to FIG. 2 but showing the sear actuated to release the firing pin;

FIG. 4 is a view similar to FIG. 3 but with the disconnector actuated by the slide to release the rear release;

FIG. 5 is a view taken along line 55 of FIG. 3;

FIG. 6 is a view taken along line 6-6 of FIG. 4;

FIG. 7 is a fragmentary side view showing the safety actuated to safe position;

FIG. 8 is an exploded view of the firing mechanism; and

FIG. 9 is an exploded view of the trigger mechanism.

Shown in the figures is a firearm having a receiver 12 in which there is slidingly disposed a telescopic bolt assembly 13 including a slide 14 and a bolt 16 having locking means (not shown) which are rotatable to and from a lock position responsive to longitudinal movement of the slide relative to the bolt. Bolt assembly 13 is energized for reciprocation in receiver 12 responsive to discharge forces through conventional means (not shown). A bore 20 extends longitudinally through bolt 16 and a firing pin 18 is slidingly disposed in such bore for reciprocation between a firing and a cock position. A spring 22 is disposed so as to. bii s firing pin 18 to the firing position,

releasably held in the cock position and the firing pin is a by a scar 24. Sear 24 is rotatingly mounted by means '7 nited States Fatent of a laterally disposed 'pin 26 in a vertical channel which is formed in the rear end of bolt 16 so as to provide communication between bore 20 and the underside of the bolt.

Firing pin 18 is provided with an annular groove 30 adjacent the rear end thereof and the rear wall of the groove is arranged to extend outwardly and rearwardly to provide a conical contact surface 32 which is contactable, as hereinafter described, with sear 24 for releasably holding the firing pin in the cock position. Sear 24 engages contact surface 32 by means of a cam surface 34 which, when the sear is in a hold position, is disposed in groove 30 for engagement with the contact surface to releasably hold firing pin 18 in cock position. Cam surface 34 is so related to the longitudinal plane passing through the axis of pin 26, both as to angularity and vertical position thereabove, that, when the cam surface is in contact with contact surface 32, the longitudinal forces imparted to firing pin 18 by spring 22 are converted to rotational forces in the sear to energize the sear for rotation in a clockwise direction to the hold position. A spring 36 is disposed between the forward wall of channel 28 and a radially disposed flat 38 located below pin 26 to bias sear 24 in a clockwise direction into position to effect engagement between contact surface 32 and cam surface 64 when firing pin 18 is moved into cock position.

Sear 24 is actuated to a firing pin release position by an actuator 40 which is rotatingly mounted in channel 28 rearwardly of the scar on a laterally disposed pin 42. Actuator 40 includes a fork portion 44 having a pair of vertically spaced tines 46 which slidingly receive therebetween a cylindrical lug 48 extending laterally from the side of scar 24, whereby rotation of the actuator is transferred to the sear. Actuator 40 is rotated by an integral arm 49 which extends downwardly therefrom for operational engagement by a trigger mechanism 50 attached to the underside of receiver 12.

Trigger mechanism 50 includes a housing 52 which is releasably attached to the underside of receiver 12 so as to be inserted through an opening 54 provided therethrough below actuator 40. Housing 52 is provided with a longitudinally disposed stepped bore 56 having a larger diameter portion 58, which extends rearwardly into the housing from the front end thereof, and a smaller diameter portion 60 which extends coaxially rearward from the larger diameter portion to an end wall 62. An annular shoulder 64 is formed at the rear end of larger diameter portion. Slidingly disposed in bore 56 is a carrier 66 having a hollow cylindrical portion 68 which is slidingly received by larger diameter portion 58 and a rod portion 70 which extends coaxially rearward from such cylindrical portion to be slidingly received by smaller, diameter portion 60. A compressible spring 7.]. is mounted over rod portion 70 and is disposed between shoulder 64 and the rear end of cylindrical portion 68 to bias carrier 66 forwardly in bore 56. A sear release 72 is slidingly disposed in cylindrical portion 68 and such sear release has an integral tongue 74 which projects upwardly from a cylindrical body 75 so as to extend through a clearance 76 in the front end of carrier 66 and opening 54 in receiver 12 for contact with the front side of arm 49. The longitudinal sides of clearance 76 are spaced sufliciently to permit the angular displacement of tongue 74 between a sear engaging and a displaced position. A bottomed well 77 extends axially into sear release 72 from the rear end thereof to receive, a compressible coil spring 78' for biasing the sear release forwardly. Forward displacement of sear release 72 is limited by contact thereof with the front end of a cover 80 which is slidingly installed on housing 52 by conventional flange and groove means to inclose the bottom side and front end of the housing. Rearward displacement of sear release 72 is limited by the rearward displacement of carrier 66 in' 'sear' engaging and displaced positions responsive to relative'longitudinal movement between the sear release'and carrier 66 through the sliding engagement of a lug 86 on sear release 72' with a cam path 88 in carrier 66. Cam patli-88 extends rearwardly into carrier 66'from the front end thereof and is substantially L-shaped in configuration to include a longitudinally disposed leg portion 90 and a foot portion 92 which extends arcuately in a clockwise direction from the rear end of the foot portion as viewed from the rear of the firearm. Whereby, when carrier 66 is actuated longitudinally relative to sear release 72, tongue 74 is rotated between the vertically disposed sear engaging position, wherein the tongue is contactable with arm 49' of actuator 40, and the displaced position wherein the tongue is moved away from any possible contact with such arm. When lug 86- is 'located in foot portion 92, tongue 74 is in the sear engaging position. Therefore, when rotation of scar release 72 is prevented, as hereinafter described, lug 86 is blocked from mow'ng along foot portion 92 and carrier 66 is consequently connected to sear release 72 so that rearward movement of the carrier is transferred directly to the sear release. Whereby, tongue 74 is actuated against arm 49 to pivot actuator 40 for rotation of sear 24 to release fin'ng pin 18.

Carrier 66 is'actuated rearwardly against the bias of spring 71 by a cable device 94 having a cylindrical housing- 96 which is receivable by a longitudinal channel 98 in the bottom of housing 52. An annular flange 100 around housing 96 is received by a mating recess in channel98 to prevent longitudinal displacement of the housing and the housing is held in channel 98 by' cover 80. Housing 96 slidingly supports a connector 102 which is fixedly attached to the end of a cable 104'. Connector 102 includes a hook 108 which extends upwardly through alongitudinal clearance 112' in housing 96 to engage an annular channel 110 in the rear end of 'rod portion 70 of carrier 72 for transferring longitudinal movement between cable 104 and the carrier. Thus, cabledevice 94 maybe easily disconnected froni'trigger mechanism 50, when it'isadvisable to replace the fireann, without disturbing the cable device.

A'left lug 11 4 and a right lug 115spaced laterally therefrom extend upwardly from the top of housing '52 to be insertable through receiver opening 54 and such lugs "support a laterally disposed axle 116 on which a disconnector 118 is mounted for pivotal displacement between a disconnect and a lock position. Disconneetor 118 includes a locking arm 119 which is extendable downwardly through an elongated aperture, 120"in i the top of housing 52 tobe received by an opening122'in carrier 66" and a channel 124'insear release 72 to prevent rotation thereof. Opening 122 and channel 124 are'di'sposed for alignment only when lug 86 is disposed in foot-portion '92 of cam path 88 and, therefore, when such opening and channel are aligned and locking'arm 119 is inserted the'rethrough, tongue 74 is in the sear engaging position and sear release 72 is connected to carrier 66 for longitudinal displacement'to'getlier as hereinbefore described. A spring .125 isdisposed between disconnector 118 and the top of housing 52 to'bias' locking arm1'19'into channel 124 when aligned tlie r'e w Disconnector 118 also includes a projection 12 6 whicliextends" upwardly into receiver '12 and which isj disposed so as to be clear of slide 14 when the slide is in the forward bolt locking position thereof and so as to be contactable by the slide, to actuate disconnector 118 to the disconnect position, when recoil movement of the slide is initiated responsive to the forces produced by the discharge of the firearm. When disconnector 118 is in the disconnect position, locking arm 119 is elevated clear of channel 124 in sear release 72 to free the sear release for rotation of tongue 74 to the displaced position. A safety 128 is pivotally disposed on a headed pin 130 extending through left lug 114 for manually camming disconnector 118 to the disconnect position. Whereby, with sear release 72 held in theforward position thereof by spring 78, any accidental pull on cable 104 will rotate tongue 74"to the disconnect position without imparting rearward movement'thereto.

Thus, when the firearm is in battery, firing pin 18is held'in cock positionby sear 24 and slide 14'is in the bolt lockposition and clear of disconnector 118. Consequent- 1y, lockingarm 119 on disconnector 118 is inserted into 'channel'124 and lug 86 is positioned in foot portion 92 of cam path 88 so'that tongue 74"is in position to contact arm49 of actuator 40 when carrier 66, which is pressed forwardly by spring 71, is pulled rearwardly by cable 104.

To discharge the firearm, cable 104 is pulled rearwardly and'such rearward movement is transferred directly to tongue 74 which, consequently, is moved against actuator 40 for rotation thereof and such rotation is transferred to "sear'24ifor release of firing pin 18 to discharge the chambered cartridge (not shown). As a result'of the dischargeforces, slide 14'is actuated rearwardly and, during the initial portion of such'rearward movement, the slide contacts 'cam projection 126 to pivot disconnector 118 to the disconnect position thereof and so elevate locking arm 119mm opening channel 124. Thereby, sear release 72 is unlocked from carrier 66 and is freed for forward travel responsive to the bias of spring 78. With the forward displacement of scar release 72, lug 86 is moved along cam path 88 from foot portion 92 thereof to swing tongue 74to thesear release position out of alignment with leg portion'49of actuator 40. Consequently, when slide 14 returns tofbatteryjlduring' the ensuing counterrecoil stroke thereof, tongue 74" is out of the way from any possible contact by actuator 40 and sear 24 is free to reengage firing pin18 when actuated'to the cock position by means not shown nor part'of this invention. The next discharge ofthe firearm, however, cannot be effected until the pull on cable 104 is released, permittingspring 71 to move carrier 66 tothe forward" position thereof. As carrier 66 moves'forwa'rdly, leg portion 90 of cam path 88 moves along lug 86 and, when foot portion 92 engages such lug, tongue 74'is swung to the sear actuating position. At th'esatne time, when channel 124 in sear release 72 becomes aligned with opening 122 in carrier 66, locking arm ,1 1 9 'ofdisconnector .118 is pressed thereinto by spring 12 5'to lock the searrelea's'e' for holding tongue 74 inthe sear engagingpos'ition and ready the firearm for another discharge when cable 104 is pulled.

The'advanta'ges of the firing mechanism of this inven: tion are readilyapparent from the above description. Becauseof the rotary c aracter of trigger mechanism 50, the cOnt'ourOf thefir'earm is increased less than if the trigger mechanismfas"in conventional designs, utilizes pivotal members! ',The connectionbetween cable 104 and sear actuator 40fis al's'o'di'rect for positive operation. Moreover, the invention" provides 'a number of beneficial, safety features fbe'cause'iif {cable 104 should be pulled, but not suflicie'ntlyto discharge the firearm, sear 24 is cammed back into full engagement with firing pin 18 to prevent any 'accidentabdischarge of th e'firearm as might easily the sear had only a partial engagement with the firing pin-because of the pull on the cable. Then, too, the firearm cannot be discharged untilslide 14 is'in for- Ward bolt'locking position when disconnector 118 is freed from contactwith the; slide to lock sear release 72 to car'- rier 66. The firing mechanism is also seen to be positive in operation, rugged in construction and easy to manufacture.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim:

1. A firing mechanism for a firearm having a reciprocable bolt assembly with a bolt and a slide, the firing mechanism including a firing pin disposed in the bolt for reciprocation therein between a cock and a firing position, spring means disposed in the bolt for biasing said firing pin to the firing position, a conical contact surface formed on said firing pin, a sear rotatably mounted on the slide adjacent said contact surface, and a cam surface disposed on said sear for contact with said contact surface for releasably blocking said firing pin in the cock position, said cam surface being so disposed that when in contact with said contact surface the forward bias of said firing pin is converted to rotation of said sear for moving said earn surface in a direction to fully contact said contact surface.

2. A firing mechanism for a firearm having a receiver and a bolt assembly with a bolt and a slide slidingly disposed in the receiver, the firing mechanism including a firing pin disposed in the bolt for reciprocation between a cock and a firing position, spring means disposed in the bolt for biasing said firing pin to the firing position, a conical contact surface formed in said firing pin by an annular groove, a sear rotatably mounted on the slide adjacent said contact surface, a cam surface formed on said sear and disposed for contact with said contact surface to releasably block said firing pin in the cock position, said cam surface being so disposed that when in contact with said contact surface the forward bias of said firing pin is converted to rotation of said sear for moving said cam surface into said groove for full contact with said contact surface, a trigger mechanism having in-line movement mounted on the receiver, and actuator means disposed in the slide in connection with said sear for contact by said trigger mechanism to convert the in-line movement thereof to rotation of said sear for release of said firing pin.

3. A firing mechanism for a firearm having a receiver and a bolt assembly reciprocable to and from a battery position, said bolt assembly including a bolt and a slide, the firing mechanism including a firing pin disposed in the bolt for reciprocation between a cock and a firing position, spring means disposed in the bolt for biasing said firing pin to the firing position, a conical contact surface formed in said firing pin by an annular groove, a sear rotatably mounted on the slide adjacent said contact surface, a cam surface formed on said sear and disposed for contact with said contact surface for releasably blocking said firing pin in the cock position, said cam surface being so disposed that when in contact with said contact surface the forward bias of said firing pin is converted to rotation of said sear for moving said cam surface into said groove for full contact with said contact surface, a trigger mechanism including a housing attachable to the receiver, a cylindrical carrier disposed in said housing for longitudinal nonrotating displacement therein, a sear release mounted for longitudinal and angular displacement in said carrier, said sear release including a hook extending upwardly therefrom, an actuator disposed for engagement by said hook and for engagement with said sear for converting longitudinal movement of said hook to rotation of said sear for release of said firing pin, cooperating cam path and lug means disposed respectively in said carrier and on said sear release for rotating said sear release to swing said hook to and from a position for contact with said actuator responsive to relative longitudinal movement between said carrier and sear release, and disconnector means having locking means to releasably lock said sear release in position for said hook to be engageable with said actuator for actuation thereof, and cam means on said disconnector means disposed for engagement by the slide for actuating said locking means to release said sear release and permit rotation thereof by said cam path and lug means to swing said hook clear of said actuator responsive to a pull on said carrier and thereby disconnect said sear from said trigger mechanism for reengagement with said firing pin.

4. The firing mechanism as defined in claim 3 wherein said disconnector means is pivotally mounted on the top side of said housing, said locking means includes a locking arm which is insertable through an aperture in the top of saidhousing and an opening in said carrier to be received by a channel in said sear release for blocking rotation thereof, and said cam means on said disconnector means is disposed to be contacted by the slide when leaving battery position for elevating said locking arm from said channel in said sear release to free said sea-r release for rotation.

5. The firing mechanism as defined in claim 3 wherein said cam path in said carrier is susbtantially L-shaped in configuration and includes a longitudinally disposed leg portion and a foot portion extending therefrom, and said lug means is disposed on said sear release so as to be received in said foot portion when said hook is in the sear actuating position and so as to rotate said sear release to swing said hook to the displaced position when said carrier is moved longitudinally relative to said sear release, and wherein said locking means includes a locking arm which is insertable through an aperture in the top of said housing and an opening in said carrier to be received by a channel in said sear release when said lug is received by said foot portion to block rotation of said sear release and thereby maintain said hook in position for contact with said actuator and connect said sear release to said carrier for transferring rearward displacement thereof to said hook for displacing said actuator to rotate said sear for release of said firing pin.

No references cited. 

